I was feeding my betta fish twice a day, and it diyed, so I brought another one, and my son told me not to feed it so much, feed it every three days, and now I see bubbles on top of the water, and it getting worst. What am I doing wrong.

Theres really nothing wrong with feeding your betta twice a day. You can feed two pellets in the morning and two at night.

Your problem was probably with water quality, what size bowl did/does your betta live in and how often do you change the water and how much is changed?

The bubbles are a good thing!!! When male bettas are happy and healthy they make bubble nests, so if a female was there it would be for their eggs. But female or no female if the male is healthy he will blow the bubbles. Congrats on the bubble nest!